This invention relates to annunciators and more particularly, it relates to a telephone annunciator which may be activated by the telephone user to respond to an incoming call.
There is a recognized need for providing a telephone user with some means for screening incoming telephone calls so that an unwanted call can be responded to without the user participating in a telephone conversation. The Walpole et al. U.S. Pat. No. 5,029,198 granted Jul. 2, 1991 describes a telephone call responding system in which the telephone user, upon receiving an incoming telephone call, selects one of a plurality of call response messages by actuating a control key of the responder system corresponding to the desired message. When activated, the responder system connects itself to the telephone line and delivers the selected message. After delivering the message, the responder system disconnects itself from the telephone line until it is once again activated by the user. Phillips U.S. Pat. No. 5,031,205 granted Jul. 9, 1991 discloses an auto response telephone system that allows the user to automatically screen calls and respond without even talking into the telephone receiver. The system may be built into a conventional telephone or it may be in a separate case and operated as an accessory. The system stores several messages. The user picks up the telephone when called to identify the caller and then, the user can either speak to the caller or automatically send one of the prerecorded messages.
A general object of this invention is to overcome certain disadvantages of the prior art and to provide certain improvements in the circuitry and operation.
In accordance with this invention, an improved device is provided for enabling a telephone user to screen incoming telephone calls and selectively avoid the need for engaging in conversation with an unwanted caller. This is accomplished by the telephone annunciator system which can be provided as a separate unit and easily installed by the telephone user to coact with the user""s existing telephone set. The annunciator is of small size and is adapted for high volume production at relatively low cost.
Further, in accordance with this invention, the annunciator is operable with an existing telephone line by connection of it between the telephone set and the line or by connecting it to any extension jack on the telephone line. Operation of the annunciator by the user does not require physical access to the annunciator by the user after it is installed.
Further, in accordance with this invention, the annunciator is activated by the user to play a recorded message by pressing a selected button on the keypad of a conventional tone dial telephone set, such as the Touchtone(trademark) telephone set. This is true in the case of a single telephone set connected with the telephone line or any extension telephone set connected with the telephone line. Preferably, this is accomplished by pressing the star (*) button on the telephone set.
Further, in accordance with this invention, if the annunciator is activated by mistake, for example, the user may deactivate it and stop the message by pressing the selected button again.
Further, in accordance with this invention, the annunciator is powered from the telephone line and need not be provided with its own battery or other separate power source. This is accomplished by a start-up power supply including a storage capacitor coupled with the telephone line for storing a charge in response to a ring signal on the line. Additionally, the annunciator is provided with a main power supply which is connected to the telephone line to receive power therefrom after the handset of the telephone is lifted from the cradle to operate the switch hooks.
Further, the start-up power supply includes a ring detector connected across the telephone line for producing a DC output voltage in response to the ring signal on the telephone line.
Further, in accordance with this invention, the start-up power supply includes a full wave rectifier connected across the telephone line through a coupling capacitor.
Further, in accordance with this invention, a time constant control circuit is coupled with the storage capacitor and the coupling capacitor to bleed the coupling capacitor so that the time constant of the circuit is reduced to provide faster operation of the off-hook detector.
A complete understanding of this invention may be obtained from the detailed description that follows taken with the accompanying drawings.